Display device

ABSTRACT

According to one embodiment, a display device includes a plurality of red subpixels, a plurality of green subpixels, and a plurality of blue subpixels, wherein, in a first direction, the red subpixel and the green subpixel, the green subpixel and the blue subpixel, and the blue subpixel and the red subpixel are arranged to be adjacent to each other, and in a second direction, the red subpixel and the blue subpixel, the blue subpixel and the green subpixel, and the green subpixel and the red subpixel are arranged to be adjacent to each other, and in the subpixels, as to subpixel columns adjacent to each other, when an image signal of the same gradation is input with respect to the subpixels of same color, brightness of one subpixel column is higher than that of another subpixel column.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2020-095484, filed Jun. 1, 2020, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Display devices including subpixels of multiple primal colors have beendeveloped.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates the structure of a display device of an embodiment.

FIG. 1B illustrates the structure of the display device of theembodiment.

FIG. 2 is a schematic view of pixel arrangement of subpixels of theembodiment.

FIG. 3 is a schematic view of pixel arrangement of the subpixels of theembodiment.

FIG. 4 is a schematic view of pixel arrangement of the subpixels of theembodiment.

FIG. 5A illustrates the pixel arrangement in a display area of thedisplay device of the embodiment.

FIG. 5B illustrates the pixel arrangement in the display area of thedisplay device of the embodiment.

FIG. 5C illustrates the pixel arrangement in the display area of thedisplay device of the embodiment.

FIG. 6A illustrates conversion of stripe pixel arrangement to SQy pixelarrangement.

FIG. 6B illustrates conversion of stripe pixel arrangement to SQy pixelarrangement.

FIG. 7A illustrates conversion of stripe pixel arrangement to SQy pixelarrangement.

FIG. 7B illustrates conversion of stripe pixel arrangement to SQy pixelarrangement.

FIG. 8 illustrates a relationship between input gradation and outputgradation of light subpixel and dark subpixel.

FIG. 9A illustrates another example of the structure of the displaydevice of the embodiment.

FIG. 9B illustrates another example of the structure of the displaydevice of the embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, a display device including: adisplay area; a plurality of subpixels disposed on the display area, thesubpixels arranged in a matrix in a first direction and a seconddirection crossing the first direction; and a controller configured todrive the subpixels, wherein the subpixels include a plurality of redsubpixels, a plurality of green subpixels, and a plurality of bluesubpixels, and, in the first direction, the red subpixel and the greensubpixel, the green subpixel and the blue subpixel, and the bluesubpixel and the red subpixel are arranged to be adjacent to each other,and, in the second direction, the red subpixel and the blue subpixel,the blue subpixel and the green subpixel, and the green subpixel and thered subpixel are arranged to be adjacent to each other, and, in thesubpixels, as to subpixel columns adjacent to each other, when an imagesignal of the same gradation is input with respect to the subpixels ofsame color, brightness of one subpixel column is higher than that ofanother subpixel column.

The present application provides a display device which can improve thedisplay quality.

Embodiments will be described hereinafter with reference to theaccompanying drawings. The disclosure is merely an example, and properchanges within the spirit of the invention, which are easily conceivableby a skilled person, are included in the scope of the invention as amatter of course. In some cases, in order to make the descriptionclearer, the widths, thicknesses, shapes, etc., of the respective partsare schematically illustrated in the drawings, compared to the actualmodes. However, the schematic illustration is merely an example, andadds no restrictions to the interpretation of the invention. In thespecification and drawings, the same elements as those described inconnection with preceding drawings are denoted by like referencenumerals, and a detailed description thereof is omitted unless otherwisenecessary.

Hereinafter, a display device of an embodiment will be explained withreference to the accompanying drawings.

In the embodiments, a first direction X, second direction Y, and thirddirection Z are orthogonal to each other; however, they may cross eachother at an angle other than 90 degrees. A direction toward the tip ofarrow of the third direction Z will be defined as up or above, and adirection opposite to the direction toward the tip of arrow of the thirddirection Z will be defined as low or below.

Furthermore, phrases such as “a second member above a first member” and“a second member below a first member” may be interpreted as the secondmember contacting the first member or as the second member being apartfrom the first member. In the latter case, a third member may beinterposed between the first member and the second member. On the otherhand, phrases such as “a second member on a first member” and “a secondmember under a first member” will be interpreted as the second membercontacting the first member.

Furthermore, an observation position to observe a display device DSP ishypothetically set in the tip side of arrow of the third direction Z,and seeing an X-Y plan view defined by the first direction X and thesecond direction Y from the observation position will be referred to asplan view. Seeing a cross-sectional view of the display device DSP alongan X-Z plan view defined by the first direction X and the thirddirection Z, or along a Y-Z plan view defined by the second direction Yand the third direction Z will be referred to as cross-sectional view.

Embodiment

FIGS. 1A and 1B illustrate the structure of the display device of thepresent embodiment. FIG. 1A is a schematic perspective view of thestructure of the display device. The display device DSP of FIG. 1Aincludes a display panel PNL. The display panel PNL is rectangular inthis example. In the example depicted, the short sides of the displaypanel PNL are parallel to the first direction X while the long sidesthereof are parallel to the second direction Y. The third direction Zcorresponds to the thickness direction of the display panel PNL. Themain surface of the display panel PNL is parallel to the X-Y plandefined by the first direction X and the second direction Y.

The display panel PNL includes a first substrate SUB1 (array substrate),second substrate SUB2 (counter substrate) disposed to be opposed to thefirst substrate SUB1, and liquid crystal layer (which is not shown)formed between the first substrate SUB1 and the second substrate SUB2.Note that a panel driver PDV (controller) configured to drive thedisplay panel PNL is mounted on the first substrate SUB1, for example.

Furthermore, a host device HST is disposed outside of the display panelPNL, and the host device HST is connected to the display panel PNL via aflexible printed circuit FPC1 and the panel driver PDV.

The display panel PNL includes a display area DA in which an image isdisplayed. In the display area DA (display panel PNL), a plurality ofpixels PX and subpixels SPX included in the pixels PX are arranged(aligned). The subpixels SPX will be described later.

The panel driver PDV as a controller is, for example, configured toreceive image signals output from the host device HST and to drive eachsubpixel SPX arranged in the display area DA based on the image signalsin order to display an image on the display panel PNL.

In the lower side of the first substrate SUB1 (that is, in the rearsurface side of the display panel PNL), an illumination device ILDconfigured to illuminate the display panel PNL is disposed. A flexibleprinted circuit FPC2 connects the illumination device ILD to the hostdevice HST. Light emitting diodes (LEDs) are used as a light source ofthe illumination device ILD, for example. In this embodiment, theillumination device ILD is disposed in the rear surface side of thedisplay panel PNL; however, a front light which is disposed in thedisplay surface side of the display panel PNL may be used. Or, anillumination device using a light guide plate and LEDs arranged in thesides of the light guide plate may be used, or an illumination deviceusing light source spots in which light emitting elements are arrangedin a plan.

Note that, in the present embodiment, the display device DSP is a liquidcrystal display device using a liquid crystal layer; however, thedisplay device DSP may be, for example, an organic electroluminescence(EL) display device using an organic light emitting layer, or a microLED display device using micro LEDs.

If the display device DSP is an organic EL display device or a micro LEDdisplay device, an illumination device may be omitted from the displaydevice DSP.

Furthermore, in the present embodiment, the display panel PNL may be atransmissive type, or reflective type, or transflective type. Thedisplay device DSP with a transmissive type display panel PNL includesan illumination device ILD in the rear surface side of the firstsubstrate SUB1 as described above, and has a transmissive displayfunction by which an image is displayed through selectively transmit thelight from the illumination device ILD. The display device DSP with areflective type display panel PNL includes a light reflection layer in afurther rear side of the display panel PNL than is the liquid crystallayer, and has a reflective display function by which an image isdisplayed through selectively reflect the light from the front surfaceside (display surface side) of the second substrate SUB2. Note that, anauxiliary light source may be disposed in the front surface side of thereflective type display panel PNL. Furthermore, the reflection layer maybe structured such that electrodes in a further rear side of the displaypanel PNL than is the liquid crystal layer are formed of a reflectivematerial such as metal. The display device DSP with a transflective typedisplay panel PNL has both the transmissive function and the reflectivedisplay function.

FIG. 1B illustrates a circuit structure of FIG. 1A. As in FIG. 1B, asubpixel SPX includes, for example, a switching element SW, pixelelectrode PE, common electrode CE, and liquid crystal layer LC.

The switching element SW is formed of, for example, a thin filmtransistor (TFT), and is electrically connected to a scan line GL and asignal line SL. The scan line GL is electrically connected to theswitching element SW of each of the pixels PX arranged in the firstdirection X. The signal line SL is electrically connected to theswitching element SW of each of the subpixels SPX arranged in theopposite direction of the second direction Y.

The pixel electrode PE is electrically connected to the switchingelement SW. The common electrode CE is provided commonly with the pixelelectrodes PE. The liquid crystal layer LC (especially, liquid crystalmolecules LCM) is driven by a field produced between the pixel electrodePE and the common electrode CE. Specifically, the same potential isapplied to the common electrode CE of the pixels PX while a voltage isapplied to the pixel electrode PE of each subpixel SPX. Capacitance CSis formed between electrodes of the same potential with the commonelectrode CE and between electrodes of same potential with the pixelelectrodes PE.

The scan line GL, signal line SL, switching element SW, and pixelelectrode PE are disposed in the first substrate SUB1. The commonelectrode CE is disposed in the second substrate SUB2. In the firstsubstrate SUB1, the scan line GL and the signal line SL are electricallyconnected to the panel driver PDV and the flexible line substrate FPC1.

In the present embodiment, the subpixels SPX include a red (R) subpixelSPR, green (G) subpixel SPG, and blue (B) subpixel SPB. FIG. 2 is aschematic view of pixel arrangement of subpixels of the presentembodiment. In FIG. 2, each of blocks arranged in a matrix in the firstdirection X and the second direction Y represents a subpixel SPXincluded in the display area DA of the display device DSP. Note that,block of R represents a subpixel SPR, block of G represents a subpixelSPG, and block of B represents a subpixel SPB.

One pixel PX includes a red (R) subpixel SPR, green (G) subpixel SPG,and blue (B) subpixel SPB. In the present embodiment, the subpixel SPR,subpixel SPG, and subpixel SPB may be referred to as first subpixel,second subpixel, and third subpixel, respectively.

In the display area DA of the display device DSP of FIG. 2, thesubpixels SPR, SPG, and SPB are arranged in this order along the firstdirection X. Furthermore, in the display area DA of the display deviceDSP of FIG. 2, the subpixels SPR and SPG, and the subpixels SPG and SPBare arranged to be adjacent to each other in the first direction X.Furthermore, the subpixels SPR and SPB, subpixels SPB and SPG, andsubpixels SPG and SPR are arranged to be adjacent to each other in thesecond direction Y.

Specifically, along the first direction X, the subpixels SPR, SPG, andSPB are arranged in this order. In the display area DA, along the seconddirection Y, the subpixels SPR, SPB, and SPG are arranged in this order.Furthermore, in the display area DA, the subpixels SPR, SPB, and SPG arearranged in this order along the second direction Y. In other words, inthe opposite direction to the second direction Y, the subpixels SPR,SPG, and SPB are arranged in this order.

In other words, in the first direction X, the subpixel SPG is disposedbetween the subpixels SPR and SPB. In the first direction, the subpixelSPB is disposed between the subpixels SPG and SPR. In the firstdirection X, the subpixel SPR is disposed between the subpixels SPB andSPG.

Furthermore, in the second direction Y, the subpixel SPB is disposedbetween the subpixel SPR and the subpixel SPG. In the second directionY, the subpixel SPG is disposed between the subpixels SPB and SPR. Inthe second direction Y, the subpixel SPR is disposed between thesubpixels SPG and SPB.

In other words, the subpixels SPX of same color are arranged to beshifted from each other by one in the first direction X and by one inthe opposite direction to the second direction Y. That is, the subpixelsSPX of same color are arranged diagonally to be shifted from each otherby one in every column and row.

That is, the subpixels SPX adjacent to each other in each subpixel rowhave different colors and the subpixels SPX adjacent to each other ineach subpixel column have different colors.

In the present application, the pixel arrangement of FIG. 2 will bereferred to as SQy pixel arrangement.

Note that, in the present embodiment, the arrangement of subpixels SPXis not limited to the example of FIG. 2, and the arrangement ofsubpixels SPX of FIG. 2 may be flipped horizontally, or flippedvertically, or flipped both vertically and horizontally.

Now, a case where the display device DSP performs raster display. In theraster display, an image of same gradation is uniformly displayed in thedisplay area DA of the display device DSP. For example, white or blue isdisplayed in the entirety of the display area DA.

In such a case, in the display device DSP in which the subpixels SPX ofsame color are arranged diagonally as in FIG. 2, the following problemmay occur.

That is, if the display device in which the subpixels SPX of same colorare arranged diagonally performs the raster display, the subpixels SPXof same color may be recognized as a continuous object as a streakextending diagonally. Such a streak is obvious if the definition of thedisplay device DSP is lower. Furthermore, apart from the raster display,such a streak will also be obvious if the part of same gradation isgreater in a display image.

Such a diagonal streak may decrease the display quality of the displaydevice DSP.

The present embodiment provides a display device which can suppress thedecrease of display quality caused by the above-mentioned diagonalstreak. In the display device DSP of the present embodiment, brightnessof adjacent subpixel columns differs in the subpixels SPX. Specifically,a column of subpixels brightness of which is higher (will be referred toas light subpixels in the present embodiment), and a column of subpixelsbrightness of which is lower (will be referred to as dark subpixels inthe present embodiment) are arranged alternately. That is, one of thesubpixel columns adjacent to each other is brighter than the other. Inother words, a dark subpixel column is disposed between light subpixelcolumns arranged every other column. In other words, the odd-numberedsubpixel column is one of a light subpixel column and a dark subpixelcolumn, and the even-numbered subpixel column is the other thereof.

Note that the light subpixel and the dark subpixel will be determinedbased on the gradation input in the subpixels SPX. The details will beexplained later.

In other words, in the subpixels SPX, the brightness of the subpixelsSPX adjacent to each other in the first direction X differs, and thebrightness of the subpixels SPX adjacent to each other in the seconddirection Y is the same. Furthermore, in the first direction X, betweentwo subpixels SPX of same brightness, one subpixel SPX of differentbrightness is disposed. The brightness of one of two subpixels SPXadjacent to each other in the first direction X is higher than that ofthe other.

FIG. 3 is a schematic view of pixel arrangement of the subpixels of thepresent embodiment. In FIG. 3, a subpixel SPX of lightly dotted is alight subpixel, and a subpixel SPX of tightly dotted is a dark subpixel.

In the display area DA of the display device DSP of FIG. 3, lightsubpixel columns and dark subpixel columns are arranged alternately. Inthe display area DA of FIG. 3, the odd-numbered column is the lightsubpixel column, and the even-numbered column is the dark subpixelcolumn. Note that the order of the odd-numbered columns and theeven-numbered columns is not limited thereto. That is, the odd-numberedcolumn may be the dark subpixel column and the even-numbered column maybe the light subpixel column.

The display area DA of FIG. 3 includes a subpixel SPRb as a lightsubpixel of the subpixel SPR, subpixel SPRd as a dark subpixel of thesubpixel SPR, subpixel SPGb as a light subpixel of the subpixel SPG,subpixel SPGd as a dark subpixel of the subpixel SPG, subpixel SPBb as alight subpixel of the subpixel SPB, and subpixel SPBd as a dark subpixelof the subpixel SPB.

For example, in the subpixels SPX of the first row of the display areaDA, along the first direction X, the subpixels SPRd, SPGb, SPBd, SPRb,SPGd, and SPBd are arranged repeatedly in this order. Furthermore, forexample, in the first column of the display area DA, along the oppositedirection of the second direction Y, the subpixels SPRd, SPGd, and SPBdare arranged repeatedly in this order. In the second column of thedisplay area DA, along the opposite direction of the second direction Y,the subpixels SPGd, SPBd, and SPRd are arranged repeatedly in thisorder.

Now, the red (R) subpixels SPR will be used in this explanation. FIG. 4is a schematic view of the pixel arrangement of subpixels of theembodiment. FIG. 4 illustrates a light subpixels SPRb and a darksubpixel SPRd of the subpixels SPR, and a streak caused by the subpixelsSPR.

Specifically, the display device DSP of FIG. 4 includes, as in FIG. 2, astreak ST1 (extending downward to the right) caused by the subpixels SPRshifted by one in the first direction X and shifted by one along theopposite direction of the second direction Y, and also a streak ST2(extending upward to the right) caused by the subpixels SPR shifted byone along the second direction Y. Note that, in FIG. 4, the streak ST1is shown in the area surrounded by a dotted line, and the streak ST2 isshown in the area surrounded by the one-dotted broken line.

The reason why the streak ST1 is as stated in the explanation of FIG. 2.The streak ST2 of FIG. 4 is caused because the dark subpixels SPRd arerecognized as a streak. As in FIG. 4, the streaks ST1 and ST2 inclinedin different directions cancel each other. As a result, both the streaks(ST1 and ST2) become difficult to recognize. Thus, a display device ofimproved display quality can be achieved.

Now, a method of converting an input to the subpixels SPX in a stripepixel arrangement into an input to the pixel arrangement of FIG. 3 willbe explained.

FIGS. 5A to 5C illustrate the pixel arrangement in the display area DAof the display device DSP of the embodiment. FIG. 5A is a schematic viewof stripe pixel arrangement. In the display device DSP of FIG. 5A, aplurality of subpixels SPX (subpixels SPR, SPG, and SPB) are arranged toeach form a stripe shape in the column direction. In other words, aplurality of subpixels SPX of each row of the pixel arrangement arearranged such that the subpixels SPX of same color are adjacent to eachother in the column direction and the subpixels SPX of different colorsare aligned in the row direction. Such a pixel arrangement is theabove-mentioned stripe pixel arrangement.

Furthermore, as stated above, since one pixel PX includes threesubpixels SPX (subpixels SPR, SPG, and SPB), it is understood thatpixels PX of one column include subpixels SPX of three columns in thedisplay device DSP of FIGS. 5A to 5C. Note that, in FIG. 5A, subpixelsSPR, SPG, and SPB, and pixel PX of the stripe pixel arrangement arereferred to as subpixels SPRp, SPGp, and SPBp, and pixel PXp,respectively.

Furthermore, the display device DSP of FIG. 5A has a resolution of1080×1920 (1080 rows×1920 columns). That is, in the display device DSPof FIGS. 5A to 5C, subpixels of 1080×1920 are arranged in each ofsubpixels SPR, SPG, and SPB.

In the display device DSP of stripe pixel arrangement, subpixels of samecolor are arranged per column, and thus, manufacturing of a member todisplay colors such as color filter of a liquid crystal device is easy,which is advantageous.

However, when the display device DSP of stripe pixel arrangement becomeshigh definition, the width of subpixel columns becomes thinner. Thus,there may possibly be a case where a sufficient area to arrange signallines SL is not secured.

Thus, in the present embodiment, the display device DSP of SQy pixelarrangement of FIG. 3 will be used. FIG. 5B is a schematic view of theSQy pixel arrangement as with FIG. 3. The display device DSP has, ascompared to the stripe pixel arrangement, ⅔ resolution in the firstdirection X, and 3/2 resolution in the second direction Y. For example,if the stripe pixel arrangement exerting the resolution of 1080×1920(1080 rows×1920 columns) of FIG. 5A is converted into the SQy pixelarrangement, the resolution becomes 1620×1280 as in FIG. 5B.

In other words, the length of one subpixel SPX in the first direction X(lateral width) becomes 3/2 of that of the stripe pixel arrangement.Similarly, the length of one subpixel SPX in the second direction Y(vertical width) becomes ⅔ of that of the stripe pixel arrangement.Since the lateral width of the subpixel SPX increases, the width of thesignal line SL can be secured.

Note that, in FIG. 5B, subpixels SPR, SPG, and SPB, and pixel PX of theSQy pixel arrangement are referred to as subpixels SPRq, SPGq, and SPBq,and pixel PXq, respectively.

However, the stripe pixel arrangement and the SQy pixel arrangement havedifferent shapes, and thus, image signals to the subpixels SPX of thestripe pixel arrangement must be converted into the image signals of theSQy pixel arrangement.

FIGS. 6A, 6B, 7A, and 7B illustrate the conversion from the stripe pixelarrangement into the SQy pixel arrangement. For easier understanding ofthe figures, in FIGS. 6A, 6B, 7A, and 7B, red subpixels SPR (SPRp andSPRq) are depicted with vertical lines, green subpixels SPG (SPGp andSPGq) are depicted with diagonal lines, and blue subpixels SPB (SPBp andSPBq) are depicted with horizontal lines.

The display device DSP of FIG. 6A includes subpixels SPX of the stripepixel arrangement, and one pixel PXp includes three subpixels SPRp,SPGp, and SPBp arranged in the first direction X.

On the other hand, the display device DSP of FIG. 6B includes subpixelsSPX of the SQy pixel arrangement. As in FIG. 6B, the pixels PXp of thestripe pixel arrangement of two rows by one column are converted intothe subpixels of the SQy pixel arrangement of three rows by two columns.

In FIGS. 7A and 7B, only red subpixels SPR (SPRp and SPRq) are shown. Asin FIG. 7A, pixels PXp included in two-row by two-column of the stripepixel arrangement will be referred to as pixels PXp (1,1), PXp (1,2),PXp (2,1), and PXp (2,2). The pixel PXp (1,1) includes subpixel SPRp(1,1), pixel PXp (1,2) includes subpixel SPRp (1,2), pixel PXp (2,1)includes subpixel SPRp (2,1), and pixel PXp (2,2) includes subpixel SPRp(2,2). Note that, in FIGS. 7A and 7B, components of the image signalinput to each subpixel SPRp are 16.

Two-row by two-column pixels PXp of the stripe pixel arrangement isconverted into three-row by four-column subpixels of the SQy pixelarrangement. As in FIG. 7B, components 16 of the subpixel SPRp (1,1)(pixel PXp (1,1)) are input to subpixel SPRq (−1,2). Note that thesubpixel SPRq (−1,2) indicates subpixel SPRq one row before the pixelPXp included in the two-row by two-column stripe pixel arrangement andsecond column subpixel SPRq.

Components 16 of the subpixel SPRp (2,1) (pixel PXp (2,1)) are input tosubpixel SPRq (1,2). Components 16 of the subpixel SPRp (1,2) (pixel PXp(1,2)) are input to subpixel SPRq (1,3). Components 16 of the subpixelSPRp (2,2) (pixel PXp (2,2)) are input to subpixel SPRq (2,4).

Note that the same conversion is performed with respect to the othersubpixels SPRp (pixels PXp).

Conversion of the components of one subpixel SPRp of the stripe pixelarrangement into one subpixel SPRq of the SQy pixel arrangement asdescribed above will be referred to as mapping process in the presentembodiment.

Note that, in the aforementioned description, the mapping process of redsubpixels SPR has been explained, and the same process is performed inthe green subpixels SPG and blue subpixels SPB. Thus, conversion of theimage signals of the stripe pixel arrangement to the SQy pixelarrangement is achieved.

Note that, in the present embodiment, the subpixels SPRp, SPGp, and SPBpmay be referred to as first red subpixel, first green subpixel, andfirst blue subpixel, respectively, and if there is no need ofdistinguishing the colors, they may be referred to as first subpixel.Furthermore, the subpixels SPRq, SPGq, and SPBq may be referred to assecond red subpixels, second green subpixel, and second blue subpixel,respectively, and if there is no need of distinguishing the colors, theymay be referred to as second subpixel.

If the image signal input to the first subpixel is a first image signal,and the image signal input to the second subpixel is a second imagesignal, in FIGS. 7A and 7B, the second image signal of one secondsubpixel is input to one first subpixel of the same color.

As above, the conversion of the image signal of the square pixelarrangement to the SQy pixel arrangement is performed. Now, lightsubpixels and dark subpixels are disposed alternately in the SQy pixelarrangement of FIG. 5B will be shown in FIG. 5C.

As in FIG. 5C, one pixel PXq includes red (R), green (G), and blue (B)subpixels. At the same time, one pixel PXq includes two light subpixelsand one dark subpixel, or one light subpixel and two dark subpixels.

FIG. 8 illustrates a relationship between input gradation and outputgradation of light subpixels and dark subpixels. FIG. 8 illustrates astate where the input gradation and the output gradation are equal witha dotted line. In the light subpixels, the image signal is processed toincrease the output gradation with respect to the input gradation. Inthe dark subpixels, the image signal is processed to increase the outputgradation with respect to the input gradation. In the light subpixelsand the dark subpixels, a difference of the output gradation becomessmall in the low gradation side, and a difference of the outputgradation becomes great in the high gradation side.

Note that, the gradation close to the maximum gradation, for example,250 or above, the output gradation of the light subpixels becomessaturated, and the output gradation becomes constant (maximum gradation)even if the input gradation is increased. In that case, the outputgradation of the dark subpixels is defined such that a difference of thegradation (brightness difference) between the dark subpixels and lightsubpixels appears. There may be a possibility that the output gradationmay not reach the maximum value in the dark subpixels even if the inputgradation is increased; however, a difference of the gradation(brightness difference) between the light subpixels and the darksubpixel should appear.

The columns of the light subpixels and the dark subpixels explained withreference to FIG. 8 are arranged alternately, and thus, the pixelarrangement shown in FIGS. 4 and 5C can be achieved. Thus, even if thestreak ST1 extending downward to the right can be canceled by the streakST2 extending upward to the right.

Note that, the display device DSP of the present embodiment may bedriven such that the polarity of the voltage applied to the pixelelectrode PE and the common electrode CE may be reversed per twosubpixel columns at a certain interval. Such a drive will be referred toas two column reverse drive in the present embodiment.

For example, if the voltage applied to the common electrode CE is areference voltage, a voltage which is higher than the reference voltage(positive (+) polarity) is applied to the pixel electrodes PE of thefirst and second subpixel columns. Furthermore, a voltage which is lowerthan the reference voltage (negative (−) polarity) is applied to thepixel electrodes PE of the third and fourth subpixel columns. At acertain interval, the polarity of the voltage applied to the pixelelectrodes PE is reversed. Note that the same drive is applied to thefifth columns and thereafter.

According to the aforementioned embodiment, a display device which canimprove the display quality can be achieved.

Structural Example 1

FIGS. 9A and 9B illustrate another example of the structure of thedisplay device of the embodiment. The example of FIGS. 9A and 9Bperforms a rendering process which is different from the example ofFIGS. 7A and 7B.

FIG. 9A is the same as FIG. 7A. In FIG. 7B, all components of onesubpixel SPRp of the stripe pixel arrangement are converted to onesubpixel SPRq of the SQy pixel arrangement. On the other hand, in FIG.9B, components of one subpixel SPRp of the stripe pixel arrangement aredistributed to be input to the subpixel SPRq of the SQy pixelarrangement. That is, unlike FIGS. 7A and 7B, in FIG. 9B, the imagesignal (corresponding to the second image signal) of one second subpixel(subpixel of the stripe pixel arrangement) are distributed to aplurality of first subpixels of same color (subpixels of the SQy pixelarrangement). The details will be explained below.

In the display device DSP of FIG. 9B, the components of one pixel PXp ofthe stripe pixel arrangement are distributed to four or more directions.Specifically, in FIG. 9B, subpixels SPRp, SPGp, and SPBp included in onepixel PXp are repeatedly distributed to every three lateral subpixelsand two vertical subpixels. Note that the three lateral subpixels areevery third subpixel in the first direction X, and the two verticalsubpixels are every second subpixels in the second direction Y.Furthermore, the components of the pixel PXp are equal to the gradationof the image signal input to the pixel PXp or the brightness of thepixel PXp.

As in FIG. 9B, components 16 of the subpixel SPRp (1,1) (pixel PXp(1,1)) are distributed to subpixel SPRq (−1,2) by three, subpixel SPRq(1,−1) by three, subpixel SPRq (2,1) by seven, and subpixel SPRq (1,3)by three. Note that the subpixel SPRq (−1,2) indicates subpixel SPRq onerow before the pixel PXp included in two-row by two-column of the stripepixel arrangement and second subpixel SPRq. Furthermore, the subpixelSPRq (1,−1) indicates the first column subpixel SPRq and one columnbefore the pixel PXp included in the two-row and two-column of thestripe pixel arrangement.

Components 16 of the subpixel SPRp (2,1) (pixel PXp (2,1)) aredistributed to subpixel SPRq (2,1) by five, subpixel SPRq (4,−1) by one,subpixel SPRq (3,2) by nine, and subpixel SPRq (4,3) by one.

Components 16 of the subpixel SPRp (1,2) (pixel PXp (1,2)) aredistributed to subpixel SPRq (−1,2) by one, subpixel SPRq (1,3) by nine,subpixel SPRq (−1,5) by one, and subpixel SPRq (2,4) by five.

Components 16 of the subpixel SPRp (2,2) (pixel PXp (2,2)) aredistributed to subpixel SPRq (3,2) by three, subpixel SPRq (2,4) byseven, subpixel SPRq (4,3) by three, and subpixel SPRq (3,5) by three.

Note that the components are similarly distributed with respect to theother subpixels SPRp (pixels PXp).

The same applies to the green subpixels SPG, and the blue subpixels SPB.

Through the aforementioned rendering process, the image signal is inputto the pixels SPXq (subpixels SPRq, SPGq, and SPBq) closer to the inputimage. Thus, the display device DSP of the present example can displayan image of higher display quality.

The present example can achieve the advantages of the embodiment.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A display device comprising: a display area; aplurality of subpixels disposed on the display area, the subpixelsarranged in a matrix in a first direction and a second directioncrossing the first direction; and a controller configured to drive thesubpixels, wherein the subpixels include a plurality of red subpixels, aplurality of green subpixels, and a plurality of blue subpixels, and inthe first direction, the red subpixel and the green subpixel, the greensubpixel and the blue subpixel, and the blue subpixel and the redsubpixel are arranged to be adjacent to each other, and in the seconddirection, the red subpixel and the blue subpixel, the blue subpixel andthe green subpixel, and the green subpixel and the red subpixel arearranged to be adjacent to each other, and in the subpixels, as tosubpixel columns adjacent to each other, when an image signal of thesame gradation is input with respect to the subpixels of same color,brightness of one subpixel column is higher than that of anothersubpixel column.
 2. The display device according to claim 1, wherein, inthe display area, the subpixel column of higher brightness and thesubpixel column of lower brightness are arranged alternately.
 3. Thedisplay device according to claim 1, wherein, along the first direction,one of the red subpixels, one of the green subpixels, and one of theblue subpixels are arranged repeatedly in this order, and along thesecond direction, one of the red subpixel, one of the blue subpixel, andone of the green subpixel are arranged repeatedly in this order.
 4. Thedisplay device according to claim 1, wherein, in the first direction,the green subpixel is arranged between the red subpixel and the bluesubpixel, the blue subpixel is arranged between the green subpixel andthe red subpixel, and the red subpixel is arranged between the bluesubpixel and the green subpixel, and in the second direction, the bluesubpixel is arranged between the red subpixel and the green subpixel,the green subpixel is arranged between the blue subpixel and the redsubpixel, and the red subpixel is arranged between the green subpixeland the blue subpixel.
 5. The display device according to claim 1,wherein, in the subpixels, the subpixels of according to same color arearranged diagonally along the first direction and an opposite directionof the second direction.